Various former experiments carried out in Komaba and Nishigahara
have shown that for several Gramineae the best ratio of lime to magnesia
lies between i/i and 2/1. With oats the yield was nearly equal in both
cases while with upland rice the ratio 1/1 was more favorable than 2/1 and
for barley before its flowering period 2/1 was more favorable. With the
development of seed, however, relatively more magnesia is required and
also in the case of barley the final ratio will be nearer to 1/1 than 2/1.

These ratios, however, correspond to equal availability of lime and magnesia,
both having been applied as natural carbonates or as nitrates. The ratio of
lime to magnesia entering the plant changes, however, very considerably when
one of the compounds is insoluble in water while the other is soluble. The
latter will then much more readily enter into the plant body than the former.

My former experiment^ with rice showed that with artificial carbonate

of lime and with magnesia as cryst. sulphate, the best ratio in sand culture

CaO as carbonate _ 30
MgO as sulphate 1

I have carried out a similar experiment with barley in sand culture,

applying the lime in the form very finely powdered lime stone. Each pot

contained 4.5 Kg of dry sand and received the following general manure

applied in five fractions :

NaN0 3 10 Gr.

K._.«0 4 10 Gr.

KH;,P0 4 15 Gt.

While the amount of lime was constant that of magnesia was varied as

follows :

1). This Bulletin Vol. I, No. i, p. 23-29.

420042

&\\6\9d

88

G. 1) i ik ii liiiia.

No. of pots.

CaO : MgO

Powdered lime stone.

MgS0 4 + 7H 2 0.

I.

5 : 1

804 g

5496 g

II.

io : I

„ ,.

274S „

III.

20 : i

., ,.

13-74 -

IV.

30 : 1

,. .,

9.16 „

V.

40 : I

t, „

6.87 „

VI

50 : 1

., „

5-50 »

VII.

60 : 1

>» >»

4 53 »

VIII.

70 : I

» "

3-44 »

The seeds of barley (var. Goldenmeloii) were sown Nov. 10, 1904 and
after germination the young plants were reduced to 6 of equal size. The
growth in all the pots started equally well but gradually differences
appeared, plants in No. I and II were far inferior in growth while the plants
in No. VII and VIII were of the most luxurient development as shown by
the following measurements made on Jan. 9, 1905. In the beginning of
February the plants in pots No. 1 died off.

Table I.

No. of Pots.

CaO : MgO.

Average length of the
longest leaves.

Average number of stalks
p. pot.

IpOt 2

5 ' 1

9.5 cm.
9.0 „

1
1

fF*>t 1

II.

IpOt 2

10 : 1

10.5 „
10.5 „

i-8
2.2

/pot I

III. {

IpOt 2

20 : 1

18.1 „

18.8 „

3-8
38

/pot I
IV. i

Ipot 2

30 : 1

20.1 „
20.1 „

4-2
4-5

• pot I

I pot 2
• •• •

40 : 1

2C.6 „

21.7 „

5-o
5-3

On the Influence of Solubility on Availability.

8 9

No. of Pots.

CaO : MeO. Average length of the
b longest leaves.

Ayerage number of stalks
p. pot.

fPOt 1
VI.

tpot 2

50 : 1

23.2 cm. 5.9
23-3 » 5-8

/•pot I
VII. J

[por 2

60 : 1

23-2 ,.
26.0 „

6.8
6.8

rpot r

VIII. 1

(pot 2

80 : 1

24-9 ,.
24.3 »

6.9
6.9

The plants were cut on June 10, dried and weighed with the following
result, to which are added the observation on the plants in pot No. I ;
these died in February.

Table II.

No. of

pots.

CaO : MgO

Number of stalks.

Number of ears.

Aver, length of stalks

p. pot.

Average.

p. pot.

Average.

of each pot

Average.

I.

J pot I
(pot 2

5 ! l

10
8

9

9
7-5

8-5

II.

jpot I

[pot 2

10 : 1

19
25

22

5

5

45-o
46.8

45-9

IIL

rpot 1

[pOt 2

20 : 1

43
42

42.5

43
39

4i

g6.o
96.0

96.0

IV.

t pot I

I POt 2

30 : 1

4 1

41

41.0

40
4 1

4 1

96.0
102.9

99-5

V.

jpot I

(pOt 2

40 : 1

36
54

45.0

35
52

44

102.0
96.6

99-3

VI.

r pot I

(pot 2

50 : 1

48
48

48.0

48
43

46

97-5
92.1

94.8

9°

G. I);i ikuliiira.

No. of pots.

CaO : MgO

Number of stalks.

Number of ears.

Aver, length of stalks.

p. pot.

Average.

p. pot.

Average.

of each pot

Average.

,pot I
VII. J

IpOt 2

6o : i

...»

5°

500

47

47

97-5

97-5

/pot I
VIII. J

(.pot 2

8o : i

51

48

49-5

5 1

47

49

93-°
98.7

95 9

Table III.

Nc. of

pot.*.

CaO : MgO

Seeds
g

Stalks
g

Chaff

g

Root
g

Total
g

Average p. pot g

Seeds

Total

I.

\fOt 2

5:1-*)

II.

fPot 1

\pOt 2

10 : 1-')

0.38

13-50
28.88

0.38

1.88

7.50

I5-38
37-M

0.3S

26.26

III.

/pot I

\p0t2

20 : 1

18 3 S
33-oo

79-50
82.88

4.50
3-75

'5-75

18.75

118.13
138.38

25.69 • 128.26

IV.

/pot I

\fOt 2

30 : 1

29.63
33 38

82.50
81.00

6.00
4-i3

18.13
16.13

136.26
134.64

?»«5> x 35-45

V.

J P°t 1

\pOt 2

40 : I

25- I 3
I5-38

72.38
121.50

3-75
4.88

16.50
29.25

117.76
171.01

20.26

144-39

VI.

jpot I

(pot 2

50: 1

24-75

28.88

10463
92.63

6.00
4-13

15-0°
13-13

150.38
138.77

26.82

14458

1). Some plants in this pot were attacked by fungus and cut off before ripening.

2). In these two cases it is very probable that not only a certain excess of available magnesia,
but also the salt concentration itself, caused the depression of the yield. All soluble salts, though
not directly injurious to the plant, would perhaps cause the dep ession when applied in such
concentration.

On tile Influence of Solubility on Availability.

9*

No. of pots.

CaO : MgO

Seeds
g

Stalks
g

Chaff
g

Root

g

Total
g

Average p. pot g

. Seed*.

Total.

,pot I

vir. J

\pOt 2

6o : I

5213

88.88

6.00

12.00

159.01

52-13

159-or

(POt I

VIII. )

\pOt 2

8o : i

40.50
4 2 -75

9S.25
91.50

6.38

4.88

18.00
1313

163.13

152.26

41.63

r 57-7°

The above result shows clearly that in the presence of lime as
carbonate, the necessary amount of magnesia applied in the form of
crystallized sulphate for barley in sand culture is so small that the best ratio
of lime to magnesia becomes 60 : 1, while in the form of nitrates of calcium
and magnesium in water culture the best ratio for Gramineae between 1/1
and 2/1. This conclusion will hold good also for various sandy soils, while

for clayey soils the best ratio is ,„ ^ ; will differ, as T. Naka-

MgO as sulphate

mura J) ascertained. The calculation from the above results shows that with
barley 4.9 parts MgSO v 7HvO are agronomically equivalent to 100 parts
magnesite, while with rice this equivalent is still higher viz. 9.8.